Study of the Correlation Between Severity of Endophthalmitis and Posterior Vitreous Detachment Using a Rabbit Endophthalmitis Model.

Purpose: We have reported that the absence of posterior vitreous detachment (PVD) is related to the onset and severity of infectious endophthalmitis, based on clinical experience. To demonstrate clinical findings in animal models, we created endophthalmitis models for the presence or absence of PVD and examined differences in severity. Method: We estimated a rabbit infectious eye model with and without PVD using Pseudomonas aeruginosa (PVD(+) and PVD(-) groups). After injection of bacteria inoculation for 3, 6, 12, and 24 hours, we evaluated the clinical score of the anterior chamber (n = 14). Removing the vitreous and retina from the enucleated eyeballs, the number of bacteria was counted using each specimen (n = 12). In addition, the number of inflammatory cells approximately 3 mm2 around the optic disc and histopathologic grading of intraocular inflammation was compared from histopathologic images (n = 7). Electroretinogram (ERG) was performed in experimentally infected rabbit eyes in both groups at three times after injection of the bacterial suspension. Results: There was no difference between the two groups in the clinical score of the anterior chamber of each time phase, but the bacterial cultures showed significantly fewer bacteria in the PVD(-) group 24 hours after bacterial inoculation (P < 0.05). Furthermore, the number of inflammatory cells was significantly less in the PVD group (P < 0.05). As a result of ERG, the decreases of a- and b-waves in amplitude were significantly greater in the PVD(-) group than in the PVD(+) group. Conclusions: The present study confirms using animal models that the absence of PVD contributed to the severity of bacterial endophthalmitis.

Microbial Signatures in The Rodent Eyes With Retinal Dysfunction and Diabetic Retinopathy.

Purpose: The gut microbiome has been linked to disease pathogenesis through their interaction in metabolic, endocrine, and immune functions. The goal of this study was to determine whether the gut and plasma microbiota could transfer microbes to the retina in type 1 diabetic mice with retinopathy. Methods: We analyzed the fecal, plasma, whole globe, and retina microbiome in Akita mice and compared with age-matched wild-type (WT) mice using 16S rRNA sequencing and metatranscriptomic analysis. To eliminate the contribution of the ocular surface and plasma microbiome, mice were perfused with sterile saline solution, the whole globes were extracted, and the neural retina was removed under sterile conditions for retinal microbiome. Results: Our microbiome analysis revealed that Akita mice demonstrated a distinct pattern of microbes within each source: feces, plasma, whole globes, and retina. WT mice and Akita mice experienced transient bacteremia in the plasma and retina. Bacteria were identified in the retina of the Akita mice, specifically Corynebacterium, Pseudomonas, Lactobacillus, Staphylococcus, Enterococcus, and Bacillus. Significantly increased levels of peptidoglycan (0.036 ± 0.001 vs. 0.023 ± 0.002; P < 0.002) and TLR2 (3.47 ± 0.15 vs. 1.99 ± 0.07; P < 0.0001) were observed in the retina of Akita mice compared to WT. Increased IBA+ cells in the retina, reduced a- and b-waves on electroretinography, and increased acellular capillary formation demonstrated the presence of retinopathy in the Akita cohort compared to WT mice. Conclusions: Together, our findings suggest that transient bacteremia exists in the plasma and retina of both cohorts. The bacteria found in Akita mice are distinct from WT mice and may contribute to development of retinal inflammation and barrier dysfunction in retinopathy.

Immune Inhibitor A Metalloproteases Contribute to Virulence in Bacillus Endophthalmitis.

Endophthalmitis is a devastating infection that can cause blindness. Over half of Bacillus endophthalmitis cases result in significant loss of useful vision. Bacillus produces many virulence factors that may contribute to retinal damage and robust inflammation. We analyzed Bacillus immune inhibitor A (InhA) metalloproteases in the context of this disease, hypothesizing that InhAs contribute to Bacillus intraocular virulence and inflammation. We analyzed phenotypes and infectivity of wild-type (WT), InhA1-deficient (ΔinhA1), InhA2-deficient (ΔinhA2), or InhA1, A2, and A3-deficient (ΔinhA1-3) Bacillus thuringiensis. In vitro analysis of growth, proteolysis, and cytotoxicity were compared. WT and InhA mutants were similarly cytotoxic to retinal cells. The ΔinhA1 and ΔinhA2 mutants entered log-phase growth earlier than WT B. thuringiensis. Proteolysis by the ΔinhA1-3 mutant was decreased, but this strain grew similar to WT in vitro. Experimental endophthalmitis was initiated by intravitreally infecting C57BL/6J mice with 200 CFU of WT B. thuringiensis or InhA mutants. Eyes were analyzed for intraocular Bacillus and myeloperoxidase concentrations, retinal function loss, and gross histological changes. Eyes infected with the ΔinhA1 or ΔinhA2 mutant strains contained greater numbers of bacteria than eyes infected with WT throughout the infection course. Eyes infected with single mutants had inflammation and retinal function loss similar to eyes infected with the WT strain. Eyes infected with the ΔinhA1-3 mutant cleared the infection. Quantitative real-time PCR (qRT-PCR) results suggested that there may be compensatory expression of the other InhAs in the single InhA mutant. These results indicate that together, the InhA metalloproteases contribute to the severity of infection and inflammation in Bacillus endophthalmitis.

COMMUNITY-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS SUBRETINAL ABSCESS IN A NONBACTEREMIC PATIENT TREATED WITH INTERNAL DRAINAGE AND RETINECTOMY.

PURPOSE: To report a case of community-associated methicillin-resistant Staphylococcus aureus subretinal abscess that continued to progress, despite intravitreal and systemic antibiotic therapy. METHODS: Retrospective chart review of a 77-year-old female patient with well-controlled diabetes mellitus who developed a left eye endophthalmitis and subretinal abscess from methicillin-resistant S. aureus colonization in the absence of any systemic focus of infection. RESULTS: The abscess and endophthalmitis resolved after the second pars plana vitrectomy that included drainage of a subretinal abscess after the failure of initial pars plana vitrectomy, and intravitreal and systemic antibiotics. Retinal detachment due to proliferative vitreoretinopathy necessitated the third pars plana vitrectomy 2 weeks after the second pars plana vitrectomy. CONCLUSION: The authors present an unusual case of methicillin-resistant S. aureus subretinal abscess in a patient with methicillin-resistant S. aureus colonization with negative blood, aqueous humor culture, and vitreous culture but a positive culture from subretinal aspirate.

PRESUMED TUBERCULOUS MULTIFOCAL RETINITIS IN PATIENTS UNDER TREATMENT WITH BIOLOGIC AGENTS.

PURPOSE: To report unique retinal fundus lesions and treatment outcomes of intraocular tuberculosis in patients under anti-tumor necrosis factor treatment. METHODS: Retrospective review of two patients with laboratorial evidence of tuberculosis who had bilateral ocular signs and symptoms not attributable to other diseases. Multimodal imaging was analyzed at the time of presentation and after the treatment initiation. The study patients underwent standard treatment for tuberculosis. RESULTS: Clinical and laboratory findings were consistent with the diagnosis of presumed tuberculosis. Color fundus photograph revealed the presence of multifocal yellowish retinal spots in the study eyes. On fluorescein angiography, the retinal lesions seen on color fundus photograph showed early hypofluorescence with progressive staining of its edges. Occlusive vasculitis with peripheral nonperfusion was also observed in both cases. Spectral domain optical coherence tomography demonstrated increased reflectivity and thickness on the topography of retinitis lesions. After specific antibiotic treatment for tuberculosis, there was complete disappearance of the retinal lesions in all study eyes. CONCLUSION: We report two unique cases of bilateral presumed intraocular tuberculosis presenting as multifocal retinitis in patients under biologic agent treatment. Anti-tumor necrosis factor agents may be related to unusual fundus manifestations of tuberculosis.

Miliary Retinal Lesions in Ocular Syphilis: Imaging Characteristics and Outcomes.

Purpose: To describe full thickness miliary retinal lesions in ocular syphilis.Methods: Retrospective chart review of patients with serologically confirmed ocular syphilis. Retinal miliary lesions in three cases of Syphilitic uveitis, in immunocompetent individuals are described. Case 1 and case 2 were positive for both VDRL (venereal disease research laboratory) and TPHA (Treponema pallidum hemagglutination), case 3 was VDRL negative but TPHA positive.Results: Miliary lesions were small round to oval, yellow retinal lesions, measuring less than » disc diameter size, with distinct margins, involving complete thickness of retina on OCT, in a pillar like manner, associated with ground glass retinitis, outer retinal placoid lesion or with retinal vasculitis. In cases 1 and 3, these healed with pigmentation.Conclusion: In contrast to similar lesions described, retinal miliary lesions seem to involve full thickness of the retina on OCT and may heal with pigmentation. These lesions may be characteristic of ocular syphilis.

Expression of Cytokines in Porcine Iris, Retina and Choroidal Tissues Stimulated by Microbe-associated Molecular Patterns.

PURPOSE: The innate immune system is strongly implicated in the pathogenesis of uveitis. This study was designed to clarify the responses of the innate immune system in uveal tissues. MATERIALS AND METHODS: We utilized quantitative, real-time RT-PCR to measure mRNA of innate immune system receptors from porcine iris, choroid, and retina tissues. We used RT-PCR for cytokines to evaluate the responses of these tissues to specific ligands or extracts of whole bacteria that activate the innate immune system. We used ELISA for IL-6 on selected choroidal supernatants to confirm that the mRNA measurement correlated with protein levels. RESULTS: In each of the studied tissues, we detected the expression of important receptors belonging to the innate immune system including dectin-1, TLR4, TLR8, and NOD2. Relative mRNA expression was generally lower in the retina compared to iris or choroid. All three tissues demonstrated upregulation of cytokine mRNA in response to a range of ligands that activate the innate immune system. The measurement of IL-6 protein was consistent with results based on mRNA. Notably, the expression of mRNA for IL-23 was more pronounced than IL-12 in all three tissues after stimulation with various innate immune system ligands. CONCLUSIONS: These data provide evidence of a potent innate immune response intrinsic to uveal tissues. Specific innate immune system ligands as well as bacterial extracts enhanced the production of several inflammatory cytokines. Furthermore, the observation of higher upregulation of IL-23 mRNA, compared to IL-12 in response to innate immune stimuli, suggested that a local TH17 response might be more robust than a local TH1 response in uveal tissues. Our results expand the understanding as to how the innate immune system may contribute to uveitis.

The role of commensal microflora-induced T cell responses in glaucoma neurodegeneration.

Over the last decade, new evidence has become increasingly more compelling that commensal microflora profoundly influences the maturation and function of resident immune cells in host physiology. The concept of gut-retina axis is actively being explored. Studies have revealed a critical role of commensal microbes linked with neuronal stress, immune responses, and neurodegeneration in the retina. Microbial dysbiosis changes the blood-retina barrier permeability and modulates T cell-mediated autoimmunity to contribute to the pathogenesis of retinal diseases, such as glaucoma. Heat shock proteins (HSPs), which are evolutionarily conserved, are thought to function both as neuroprotectant and pathogenic antigens of T cells contributing to cell protection and tissue damage, respectively. Activated microglia recruit and interact with T cells during this process. Glaucoma, characterized by the progressive loss of retinal ganglion cells, is the leading cause of irreversible blindness. With nearly 70 million people suffering glaucoma worldwide, which doubles the number of patients with Alzheimer's disease, it represents the most frequent neurodegenerative disease of the central nervous system (CNS). Thus, understanding the mechanism of neurodegeneration in glaucoma and its association with the function of commensal microflora may help unveil the secrets of many neurodegenerative disorders in the CNS and develop novel therapeutic interventions.

Toll-like receptor 2 (TLR2) engages endoplasmic reticulum stress sensor IRE1α to regulate retinal innate responses in Staphylococcus aureus endophthalmitis.

Endoplasmic reticulum (ER) stress response has been implicated in a variety of pathophysiological conditions, including infectious and inflammatory diseases. However, its contribution in ocular bacterial infections, such as endophthalmitis, which often cause blindness is not known. Here, using a mouse model of Staphylococcus (S.) aureus endophthalmitis, our study demonstrates the induction of inositol-requiring enzyme 1α (IRE1α) and splicing of X-box binding protein-1 (Xbp1) branch of the ER-stress pathway, but not the other classical ER stress sensors. Interestingly, S aureus-induced ER stress response was found to be dependent on Toll-like receptor 2 (TLR2), as evident by reduced expression of IRE1α and Xbp1 mRNA splicing in TLR2 knockout mouse retina. Pharmacological inhibition of IRE1α using 4µ8C or experiments utilizing IRE1α-/- macrophages revealed that IRE1α positively regulates S aureus-induced inflammatory responses. Moreover, IRE1α inhibition attenuated S aureus-triggered NF-κB, p38, and ERK pathways activation and cells treated with these pathway-specific inhibitors reduced Xbp1 splicing, suggesting a positive feedback inhibition. In vivo, inhibition of IRE1α diminished the intraocular inflammation and reduced PMN infiltration in mouse eyes, but, increased the bacterial burden and caused more retinal tissue damage. These results revealed a critical role of the IRE1α/XBP1 pathway as a regulator of TLR2-mediated protective innate immune responses in S aureus-induced endophthalmitis.

Clinical features and outcome of hepatosplenic fungal infections in children with haematological malignancies.

Hepatosplenic fungal infection (HSFI) is a severe invasive fungal infection observed during neutrophil recovery in patients with acute leukaemia treated with intensive chemotherapy. Retrospective analysis including all paediatric haematological malignancies patients with HSC treated in Children Cancer Hospital Egypt (2013-2018). Twenty-five patients with acute leukaemia developed HSFI (19 patients diagnosed as hepatosplenic candidiasis). Most of the cases (92%) occurred during the induction phase. Organs affected were as follows: liver in 18 patients, renal in 13 patients, spleen in 12 patients, skin in four patients and retina in one patient. Five (20%) patients had proven HSC, 14 (56%) probable and six (24%) possible HSFI. Ten patients had a PET-CT for response assessment. Candida tropicalis was the most common isolated spp. from blood/tissue culture. Six (24%) patients developed HSFI on top of antifungal prophylaxis. Steroids were given in 12 (52%) patients with HSFI as immune reconstitution syndrome (IRS). Caspofungin was the first line of treatment in 14 (56%) patients, liposomal amphotericin B in six (24%) patients and azoles in five (20%) patients. HSFI was associated with delayed of intensification phase of chemotherapy (median 42 days). The success rate was reported in 24 patients with complete response (68%) and partial response in (28%) patients, while failure (death) seen in 1(4%) patient. HSC is still a major challenge in paediatric leukaemias patients with impact on treatment delay and survival outcome. PET scan, non-culture diagnostics and steroid role evidence in IRS are growing. Antifungal stewardship for screening, early detection for high-risk patients and better response assessment is challenging.

S-layer Impacts the Virulence of Bacillus in Endophthalmitis.

Purpose: Bacillus causes a sight-threating infection of the posterior segment of the eye. The robust intraocular inflammatory response in this disease is likely activated via host innate receptor interactions with components of the Bacillus cell envelope. S-layer proteins (SLPs) of some Gram-positive pathogens contribute to the pathogenesis of certain infections. The potential contributions of SLPs in eye infection pathogenesis have not been considered. Here, we explored the role of a Bacillus SLP (SlpA) in endophthalmitis pathogenesis. Methods: The phenotypes and infectivity of wild-type (WT) and S-layer deficient (ΔslpA) Bacillus thuringiensis were compared. Experimental endophthalmitis was induced in C57BL/6J mice by intravitreally injecting 100-CFU WT or ΔslpA B. thuringiensis. Infected eyes were analyzed by bacterial counts, retinal function analysis, histology, and inflammatory cell influx. SLP-induced inflammation was also analyzed in vitro. Muller cells (MIO-M1) were treated with purified SLP. Nuclear factor-κB (NF-κB) DNA binding was measured by ELISA and expression of proinflammatory mediators from Muller cells was measured by RT-qPCR. Results: Tested phenotypes of WT and ΔslpA B. thuringiensis were similar, with the exception of absence of the S-layer in the ΔslpA mutant. Intraocular growth of WT and ΔslpA B. thuringiensis was also similar. However, eyes infected with the ΔslpA mutant had significantly reduced inflammatory cell influx, less inflammatory damage to the eyes, and significant retention of retinal function compared with WT-infected eyes. SLP was also a potent stimulator of the NF-κB pathway and induced the expression of proinflammatory mediators (IL6, TNFα, CCL2, and CXCL-1) in human retinal Muller cells. Conclusions: Taken together, our results suggest that SlpA contributes to the pathogenesis of Bacillus endophthalmitis, potentially by triggering innate inflammatory pathways in the retina.

Microbiome and Autoimmune Uveitis.

Commensal microbes affect all aspects of immune development and homeostasis in health and disease. Increasing evidence points to the notion that the gut commensals impact not only intestinal diseases but also diseases in tissues distant from the gut. Autoimmune or non-infectious uveitis is a sight-threatening intraocular inflammation that affects the neuroretina. It is strongly T cell driven, but the precise causative mechanisms are not fully understood. We and others observed that depletion of gut microbiota in animal models of uveitis attenuated disease. Using a spontaneous model of the disease, we questioned how retina-specific uveitogenic T cells are primed when their cognate antigens are sequestered within the immune privileged eye. The data suggested that gut commensals provide a signal directly through the retina-specific T cell receptor and cause these autoreactive T cells to trigger uveitis. This activation of retina-specific T cells in the gut appears to be independent of the endogenous retinal antigen. Rather, the findings point to the notion that gut microbiota may mimic retinal antigen(s), however, the actual mimic has not yet been identified. Microbiota may also serve as an "adjuvant" providing innate signals that amplify and direct the host immune response for development of uveitis. In contrast, spontaneous uveitis that develops in AIRE-/- mice appears to be independent of gut microbiota. To date, available data on human microbiota in association with uveitis are very limited and causative relationships are difficult to establish. This review will summarize the current knowledge on the role of microbiome in uveitis and its underlying mechanisms, and discuss unresolved questions and issues in an attempt to explore the concept of gut-retina axis.

A CASE OF INTRAVESICAL BACILLUS CALMETTE-GUERIN-RELATED ENDOPHTHALMITIS AND RETINITIS CONFIRMED WITH RETINAL BIOPSY.

PURPOSE: To present a rare case of bilateral endogenous chorioretinitis and unilateral endophthalmitis due to Mycobacterium bovis in a patient who received intravesical bacillus Calmette-Guerin (BCG) treatment. METHODS: We present a case of a single male patient with bilateral endogenous chorioretinitis due to Mycobacterium bovis in a patient who received intravesical BCG, an attenuated strain of M. bovis widely used to treat superficial bladder cancer. The patient underwent intravitreal tap, vitrectomy, and chorioretinal biopsy with histologic examination. RESULTS: The patient presented with a visual acuity of light perception in the right eye and 20/25 in the left eye. Examination of the right eye revealed dense vitreous haze, whereas the left eye demonstrated multifocal, yellow, round subretinal pigment epithelial lesions in the macula. The patient underwent a vitreous tap with injection of antibiotics and was admitted to the hospital for empiric systemic antibacterial and antifungal treatment along with an endogenous endophthalmitis workup. His systemic evaluation and vitreous tap did not identify a causal organism, and the eyes failed to improve on empiric therapies. He underwent pars plana vitrectomy and retinal biopsy of the right eye that revealed vitreal and infiltrative retinal acid-fast bacilli. Cultures confirmed M. bovis to be susceptible to ethambutol, rifampin, and isoniazid. After starting antimycobacterials, his vision improved to finger counting in the right eye, and his vision and appearance of the lesions remained stable in the left eye at postoperative month one. CONCLUSION: Intravesical BCG stimulates a local cell-mediated response that destroys malignant cells. It is generally well tolerated, although it rarely can result in secondary systemic infection. Intravesical BCG-related endophthalmitis is rare and should be considered in the setting of ocular inflammation in patients with a history of bladder cancer who may not disclose previous treatment with BCG.

Acute subretinal abscess in Staphylococcus aureus septicaemia with endophthalmitis showcased by multimodal retinal imaging and with 2-year follow-up.

A middle-aged man presented to emergency services with central vision loss in the setting of flu-like illness with fever. A striking subfoveal abscess was observed in the right fundus. Focal acute chorioretinal inflammation was noted in the asymptomatic fellow eye. Staphylococcus aureus septicaemia was subsequently diagnosed. He presented with undiagnosed HIV infection and latent syphilis. Serial high-definition multimodal retinal imaging showcased resolution of the dome-shaped subretinal abscess following treatment with intravenous flucloxacillin. A chorioretinal scar swiftly replaced the subfoveal abscess. Peripheral right vision and full left vision was retained. Vision loss due to endogenous endophthalmitis in systemic sepsis is an emergency requiring prompt multidisciplinary care. Sight and life are at risk-thus this is not a diagnosis to miss! Early recognition is paramount to health and in retaining vision. We briefly review relevant literature and portray how multimodal imaging guided response to treatment of acute subretinal abscess.

Long-term intake of Lactobacillus paracasei KW3110 prevents age-related chronic inflammation and retinal cell loss in physiologically aged mice.

Age-related chronic inflammation is a major risk factor for the incidence and prevalence of age-related diseases, including infectious and neurodegenerative diseases. We previously reported that a lactic acid bacteria, Lactobacillus paracasei KW3110, activated macrophages and suppressed inflammation in mice and humans. In this study, we investigated whether long-term intake of heat-killed L. paracasei KW3110 modulated age-related inflammation and altered the gut microbiota in physiologically aged mice. Compared with age-matched control mice, fecal analyses of gut microbiota revealed that intake of L. paracasei KW3110 mitigated age-related changes of beneficial bacterial composition, including the Bifidobacteriaceae family. L. paracasei KW3110 intake also mitigated age-related immune defects by reducing the prevalence of interferon-gamma (IFN-γ) -producing inflammatory CD4-positive T cells in the lamina propia of the small intestine, and reduced serum levels of proinflammatory cytokines. Furthermore, L. paracasei KW3110 intake suppressed retinal inflammation by reducing proinflammatory cytokine-producing macrophage, and age-related retinal cell loss. Taken together, these findings suggested that L. paracasei KW3110 mitigated age-related chronic inflammation through modulation of gut microbiota composition and immune system functions in aged mice, and also reduced age-related retinal ganglion cell (RGC) loss. Further studies are needed to evaluate the effect in age-related senescent changes of the retina.

Isavuconazole for Treatment of Experimental Fungal Endophthalmitis Caused by Aspergillus fumigatus.

Fungal endophthalmitis remains a significant cause of vision impairment and blindness. Moreover, the prognosis is poor, in part due to delay in diagnosis and to limited availability of effective antifungal agents with good ocular penetration. Thus, it is imperative to evaluate the therapeutic efficacy in fungal endophthalmitis of newer antifungal agents. In this study, we assessed the efficacy of isavuconazole in treating Aspergillus fumigatus endophthalmitis in an exogenous mouse model of the disease. Briefly, endophthalmitis was induced by intravitreal (IVT) injection of A. fumigatus spores into immunocompetent C57BL/6 (B6) mouse eyes. Mice were randomized into five groups that received isavuconazole via (i) oral gavage, (ii) IVT injections, (iii) intravenous injection, (iv) IVT injection followed by oral gavage, and (v) IVT injection followed by intravenous injection. Our data showed that isavuconazole treatment via all routes reduced fungal burden in A. fumigatus-infected eyes. This coincided with the preservation of retinal structural integrity (histology analysis) and retinal function (electroretinography [ERG] analysis), resulting in significantly improved disease outcome. Furthermore, isavuconazole treatment reduced the levels of inflammatory cytokines (tumor necrosis factor α [TNF-α], interleukin 1ß [IL-1ß], and IL-6) and cellular infiltration in the eyes. Notably, oral administration of isavuconazole was as effective in ameliorating endophthalmitis as intravitreal injection of the drug. Collectively, our study demonstrates that isavuconazole is effective in treating A. fumigatus endophthalmitis in mice, indicating its potential use in human ocular infections.

Endogenous Cryptococcus neoformans endophthalmitis with subretinal abscess in a HIV-infected man.

To report a rare case of Cryptococcus neoformans endogenous endophthalmitis with subretinal abscess in a 36-year-old HIV-positive man, referred with progressive blurred vision in his right eye for the last 6 months. Vitreous biopsy followed by intravitreal ganciclovir did not result in significant improvement. Microbiology revealed the presence of C. neoformans, and intravitreal amphotericin B was then administered. The patient was treated aggressively with systemic and intravitreal antifungals but had a poor visual and anatomical outcome. A high degree of clinical suspicion combined with microbiological evaluation helped to arrive at an appropriate diagnosis.

Autoreactive T Cells in Immunopathogenesis of TB-Associated Uveitis.

Purpose: Intraocular inflammation in tuberculosis-associated uveitis (TBU) is usually widespread, and responds unpredictably to treatment. Herein, we analyze the intraocular T-cell response in TBU for its surface phenotype, antigenic specificity, and functional characteristics to explain the above observations. Methods: We isolated T cells from vitreous humor samples of patients with TBU and non-TB uveitis (controls). These were directly stained for surface markers CD4, CD8, CD45RO, CD45RA, CCR7, as well as intracellular cytokines IFN-γ, TNF-α, and IL-17 and analyzed on flow cytometry. Antigenic specificity was determined by activating with Mycobacterium tuberculosis-specific antigen Early Secreted Antigenic Target-6 (ESAT-6) or retinal crude extract (RCE). Activation-induced cell death (AICD) characteristics of each T-cell population were analyzed by staining for PI-Annexin V, Fas-FasL, phospho-Akt, and phospho-Erk1/2. Results: Immunophenotyping of vitreous humor samples demonstrated polyfunctional effector and central memory CD4+ T helper cells coexpressing IFN-γ, TNF-α, and IL-17. Both ESAT-6 and RCE (autoreactive) specificity was found in T cells extracted from TBU samples; however, the mycobacterial and autoreactive T-cell populations differed in their sensitivity to AICD. Autoreactive T cells appeared to resist AICD through decreased expression of apoptotic markers, FasL and caspase-3, sustained phosphorylation of Akt, and lowered Erk1/2 activity. Conclusions: Autoreactive T cells are present in TBU eyes and are relatively resistant to AICD. An understanding of this epiphenomenon could be crucial in planning treatment of TBU patients, and interpreting response to anti-TB therapy.